Duplex wireless telegraphy.



G. MAROONI. DUPLEX WIRELESS TELEGEAPHY.

APPLICATION FILED MAY 1, 1912. 1, 1 1 ggg, Patented Nov. 3, 1914.

2 SHEETS-SHEET 1.

5002/54 w AM/Pcwv/ G. MARUONI. DUPLEX WIRELESS TELEGRAPHY. APPLICATIONFILED MAY 1. 1912.

1,1 16,309 I Patented Ndv. 3, 1914.

2 SHEETS SHEET 2.

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GULIELMO MARCOM, OF LONDON, ENGLAND, ASSIGNOR TO MARCONI WIRELESSTELEGRAPH COMPANY OF AMERICA, 0 NEW YORK, N. Y.,. A CORPORATION OF NEWJERSEY,

misses.

To. all whom it may con-0cm Be it known that LGUoLmnMo MAnoouI, asubject of the King of Italy, resid ng in London, England, have inventedcertain new an'd useful Improvements in Duplex lVireless Telegraphy, ofwhich thefollowing is a specification.

The object of this invention is to provide a duplex system of wirelesstelegraphy such that messages may be sent to and received from a distantstation simultaneously without interference. In such asystem it isnecessary to have separate transmitting and receiving apparatus at anyone station; and when messages are to be sent over great distancesit isnecessary to produce vibrations of great magnitude. Butthe proximity ofthe transmitting apparatus to the receiving apparatus in any one stationresults in the transmission of vibrations of such magnitude from thetransmitting, apparatus to the receiving apparatus. in the same station,that it is'-diflicult, if not impossible, tocause the receivingapparatus to respond to the s1gmile of the distant station.

results by combining the. aerials at the receiving station in a certainmanner, by loeating the aerials at the statlons 1n certaln relativepositions to each other and by con necting the apparatus in amannerwhich will be more fully hereinafter explained.

In my Letters Patent No. 924,168, issued June 8, 1909, I showed thatHertzian waves could be'directed bylocating the acrials 111- certainpositions relatively-to: each other, and I there showedthat the maximumeifect in given direction could be. obtained by using-an aerialsubstantially horizontal to the surface of the earth and pointing awayfrom the direction inwhich the signals were to be directed. By pointingaway, I mean that the end of the aerial which is earthed Specificationof Letters Patent; Application filed May 1, 1912. Serial No. 694,347.

DUPLEX WIRELESS TELE GRAPHY.

Patented Nov. 3, item.

I station to which it was desired to send the flmessages, and'thattheainearthed'or free end of, the aerial .is placed farthest fromthe distanti station. Inlthes'eLetters Patent I also showed thatthemaximum effect was obtained at a receiving station by locating the'aerlal at that station horizontally in the same vertical plane as, andpointing away from,the sending aerial; In this position the grounded orearthe'd end of the receiving aerial is placed nearest the distanttransmitting station and the free or unearthed end farthest from'it. InFigure3 of 'saidLetters Patent I showed an arrangement consisting of aplurality'of horizontal aerials radiating in different directions, butonly one of which, could be used. at any onetime as a sending orreceiving aerial, dependin upon the position of the distant station towhich it was desired to send or from which it was desired to receive. I5

In the drawings accompanying this specification I have shown in "l ,adiagram illustrating the relative positions of the aerialsin twostations arranged according to my present invention. In Fig.- 2 I haveshown more in detail the apparatus ofone of the stations, it being,however, shown diagrammatically for the purpose of illustratingapparatus which is operative, it being obvious that 'almost any standardtransmitting or receiving apparatus may be used in connection with theaerials shown and that many of theconnectionsmay be varied withoutafiecting the operation of the system.

Referring to Fig. 1, Ihave shown at T A the transmitting aerial of astation, say sta tion No.- 1, which is preferablylocated horizontallyand is grounded at one end. At R A, I have shown the receiving aerial atthe same station which is also preferably horizontal and parallel to T Aand is located a short distance from TA, and preferably at the side of TA, and thus'receives the minimum effect from it. At BIA I have shown athird aerial which I: will term the balancing aerial. This aerial isgrounded a t-one end and is preferably horizontal and arranged to pointaway from the plane of the transmitting aerial T A In thisposition itreceives the maximum ornearly the maximum effect from aerial T A Thesethree aerials T A,, R A and B A,, constitute the three-aerials of onestation. The receiving'a'n balancing aerials are located in the sameplace, and combined with each othe'i b'ut are removed a short distancefrom the trah'smittingaerial. This distance may I be a fraction of thedistance. of the station from the distant. station with which it is tocqmmunicate, I have found that good resuits are obtainedby separatingthese aerials oscillating with their own natural frequency which howeveris not that of these waves. At R-A I have shown the receiving aerial ata distant station, say station No. '2, with which the station firstdescribed (No. 1) is v to communicate. This aerial is arranged to pointaway from the transmitting aerial T A, and is preferably arrangedhorizontally and in the same vertical plane as T A, as shown in myLetters Patent No. 924,168

- and thus obtains the maximum effect of the transmitting aerial T A,.It is, of course, unnecessary that the receiving aerial be in exactlythesame plane as the transmitting aerial, substantial coincidence of planebeing sufficient. Located at the same place as and combined with aerialR A is a balancing aerial B A preferably arranged horizontally andpointing away from T A,. It is preferably also at'right angles to thetransmitting aerial T A, and consequently is only very slightly, if atall, affected by the signals sent from aerial T A,. Located a shortdistance from the receiving and balancing aerials R A and B A is theirtransa mitting aerial T A which is designed to transmit to the receivingaerial R A, of the distant station. T A is preferably placedhorizontally in the same vertical plane as, and pointing away from,receiving aerial R A,. The relative positions of the aerials arepreferably as follows: Transmitting aerial T A is parallel to receivingaerial R A,, at right angles to balancing aerial BA and in the sameplane as and pointing away from receiving aerial R A:. to'which maximumeffect.

it transmits, so as to transmit to it with Receiving aerial R A is inthe same plane as, and points away from, transmitting aerial T A,, so asto obtain the imaximum effect from that aerial, but is par- 130 allel toits own transmitting aerial T A so as to receive with minimum effectfrom it. Balancing aerial B A is at right angles to transmitting aerialT A,, so as to receive a withminimum effect from it, and points awayfrom its own transmitting aerial T A in order to receive therefromthejmaximnm effect. The fact that balancing aerial B A and transmittingaerial T A and balancing aerial B A 'and transmitting aerial T A, arenot located in the same planes has little effect as to. the transmittingand balancing aerials of each station are in such close proximity. The.relative locations of transmitting aerial T A and balancing aerial B A,and receiving aerial R A, are preferably the sam'e as thosedescribed'above, the transmitting aerial T A being in the same plane asand pointing away from receiving aerial R A,, and the balancing andreceiving aerials B A and R A, being preferably perpendicular to eachother. It is preferable to locate thebalancing aerial at a less heightthanthe receiving aerial at the same station, as it will therefore beaffected to a less degree by the transmitting apparatus at the distantstation.

Fig. 2 shows the general arrangement of I one of the stations, say,station No. l, the arrow indicating the direction of station No. 2 towhich it is desired to transmit and from which it is desired to receive.T A, contains the primary, a transformer 1,

so that an inductive coupling may be made with an oscillation circuitcontaining the secondary, 2, a producer of electrical oscil- Aerial.

lations of high frequency, indicated at 3, variable condenser l, sourceof power 5, and

sending key 6. I prefer to inductively couple the oscillation circuit tothe aerial, although any other method of coupling may be used, and theoscillation circuit may take any form. The receiving apparatus at thisstation preferably consists of the following apparatus, although anysuitable receiving apparatus may be used instead, the drawing beingmerely diagrammatic of the form I'preferably employ. The receivingaerial R A, has in it the primary of a transformer 7, and the balancingaerial B A, has in it the primary of a transformer 8, the primaries ofboth being adjustable. It will be noted that the circuits of theseaerials are so arranged that the effect of the oscillations in oneaerial is opposed by the effectin the other aerial. Surrounding theprimaries 7 and 8 is the secondary of a transformer 9 which is includedin the receiving "circuit, which circuit preferably contains a variablecondenser 10, and a detector ll which actuates a telephone or othersuitable instrument 12. Inasmuch as the transmitting and receivingapparatus at the same station may be separated several miles from eachother, and inasmuch as I preferably locate the operators at thereceiving apparatus of the station, I provide means for actuating andcontrolling the transmitting apparatus from the location of thereceiving apparatus. This means I have shown in the form of a telegraphline .consisting of Wires 13 ex- Lilli-3,39%,- an

' ten-ding between the location of thereceivapparatus 1301130611 8 thesignals frorn the distant transmitting aerial T A, without opposite, itis preferable that the phase aerial T A ing and transmitting ends, abattery 14, and a key 15 adapted to close the circuit and energize anelectro-magnet 16 thus actuating key 6.

The operation of my invention is as follows: Assuming that both stations1 and 2 are sending and receiving simultaneously, transmittingaerial T Awill be sending out signals to the-distant "station (No. 2), the maximumsi the arrow. wing to the proximity of the receiving and balancingaerials R A, and B A,, they will also receive the; signals emanatingfrom the transmitting. aerial -T A Balancing aerial B A,, however, beingpointed away from the transmitting aerial T A will receive the maximum,or

very nearly the maximum signal, while receiving aerial R A, beingpointed away from -'transmitting aerial T A,, will receive the maximumsignal received at station No. 1 from that transmitting aerial, as wellas strong signals from the transmitting aerial T A owing to itsproximity. The effect I produced inbalancing aerial B A, by thetransmitting aerial-TA is, however, opposite to that produced by thetransmitting aerial T A, in the receiving aerial R A,, and thus if theinductance, capacity, resistance and coupling of balancing aerial B A,be properly adjusted, and-if the ,periodicity of balancing aerial B Aand receiving aerial R A are the same, the

effect of the'transmitting aerial upon the balancing. and receivingaerials can he made equal and opposite, and thus counterbalance eachother, so that no effect is obtained in the receiving pircuit from thelocal trans.- mitting aerial. This allows the receiving any interferencefrom transmitting. aerial balancing and receiving aerials be equal andrelation of theoscillations in the two aerials be the same. The relationof these. phases depends on the relation of the respective.

distances of the balancing and receiving aerials from the transmittingaerial at any one station, and these distances may be als being in thedirection of,

In order that the eifectsin the v i It is not necessary for the practiceof my invention that all of the aerials be directiye, it is possible toobtain similar: results using one vertical aerial and one directive, thebalancing aerial, however, beingpreferably horizontah In general, betterresults are secured when all of the aerials are directive as described.

I do not. intend to limit myself tothe precise details-shown anddescribed as it is ohvious that they maybe-. variedwithin wide; limitswithout departing from thespirit of my invention. For instance, morethan one aerial may be used in each location, and wherever I- have usedthe term aerial in this specification, I have intended to include aplurality ofiaerialscooperating to produce the same. result.- Othermodifications that may be made are, .for instance, changes in thereceiving and transmitting circuits, for difierent connections may beused therein to produce the same results, a large number of, differentarrangements being known to the art, or other apparatus maybe used ,in,several of the locations, a large nu1nber'-.of d-i't. ferent. detectors,etc, being now used, or the coupling may be varied, instead of being asshown in Fig. 2, the coils-of the transformer may be arrangedconcentrically or an elec-' trostatic or other form of coupling may beused.

While I have shown the receiving, trans mitting and, balancing aerials.as being grounded or earthed as at E, yet it is not es sential to thepractice of my invention-that any of them be grounded for they may beconnected to capacities or the transmitting and receiving aerials may beconnected to capacities or the earth and thebalancing aerial prolongedin the directionof the local transmitting aerial without being grounded.7 Vl hat I claim and desire to secure by Letters Patent is:

1. In a station the'combination of transmitting apparatus,

for wireless telegraphy,

receiving apparatus comprising two aerials I disposed at an angle toeach other and means for opposing the. effect produced by thetransmitting apparatus inone aerial by the effect produced by thetransmitting apparatus in the other aerial.

2. In a station for wireless telegraphy, the combination of transmittingapparatus, receiving "apparatus comprising a receiving aerial and abalancing aerial at least one of said aerials being directive and meansfor opposing the effect produced by the trans mitting apparatus in thereceiving aerial by the effect produced by the transmitting apparatus inthe balancing aerial.

3. In a station for wireless telegraphy, the combination of transmittingapparatus,

receiving apparatus comprisingtwo aerials" I removed a short but noteach an equal dis-.

tance from the transmitting apparatus and-- means for opposing theeffect produced the transmitting apparatus in one, aerial by theeffectpro'duced by the transmitting apparatus'. inthe other aerial; 4:In' a Lstation for wireless t'e'legraphy,

\ the combination of transmitting apparatus,

receiving apparatuscomprising two aerials paratus in the other aerial.

,, ing aerial pointed at-an angle to one an.

pointed at'fan angle to one another and means for opposing theeffect'producedby the transmitting apparatus in one aerial by the effectproduced by the transmitting ap- 5. In a station for wirelesstelegraphy, the combination oftransmitting apparatus;receivingfapparatus removed a short' d1sjta-nce' from the transmittingapparatus and comprisinga receiving aerial and; a balancother, and meansfor opposing the effect produced by the-transmitting apparatus in thereceiving aerial by the effect produced by ,the transmitting apparatusin the -balancing aerial.

6.111 a station for Wireless .telegraphy,-

the combination oftransmitting apparatus, receiving apparatus removed ajshort distance from the transmitting. apparatus, and comprisingga'receiving aerial and a balancing aerial tuned tothe. same periodicity atleast one of said aerials being directive, and means for opposing theeffect produced by the transmitting apparatus in one aerial by theeffect produced by-the transmitting apparatus in the other aerial.

'7. In a station for wireless telegraphy, the combination oftransmitting apparatus,

.-1"eceiving apparatus comprising a receiving -aer1al'a1 d a balancingaerial pointed at an angle to one another and tuned to the sameperiodicity, and means for opposing the effect produced. by thetransmitting appa- "ratus in the receiving aerial by the efi'ectproduced by the transmitting apparatus in the balancing aerial.

8. Ina station for wireless .telegraphy, the combination of transmittingapparatus, receiving apparatus removed 'a short distance' from thetransmitting apparatus and "comprising a. receiving aerial and abalancing aerial pointed at an angle to one another and tuned to thesame periodicity, and means for opposing the effect produced by thetransmitting apparatus in the receiving aerial by the effect produced bythe transmittingapparatus inthe balancing aerial.

9. In a station for wireless telegraphy, receiving apparatus comprisingtwo horizontal aerials pointed at an angle to one another and areceiving circuit coupled to both.

10. In a station for wireless telegraphy, receiving apparatus comprisinga receiving aerial, a balancing aerial and a receiving circuit-coupledtoboth receiving aerial and balancing aerial at least one of saidaerials being directive.

= receiving apparatus comprising "11. In a' station for wirelesstelegraphy, receivingapparatus comprising a receiving aerial, abalancing aerial pointed at an angle to'the receiving aerial, andareceivi ng cir;

fcuit coupled. to both receiving and balanci g fl aerials.

12; In a station for wireless telegraphy, transmitting apparatuscomprising an' aerial,

aerial, a balancing aerial an a receiving circuit-coupled to bothreceiving and bal' .ancing aerials at least oneof said'aerials in thereceiving apparatus being directive.

13.-In a station for wireless telegraphy, transmitting apparatuscomprising an aerial,

a' receiving receiving. apparatus comprising a receiving aerial, abalancing'aerial and a receiving C11 cuit coupled to both receiving andbalancing serials and means for'opposingthe effect produced by thetransmitting apparatus in the receiving aerial by the effect produced bythe transmitting apparatus in the baiancing aerial-at least one of. saidaerials in the receiving apparatus being directive.

14. In a station for wireless telegraphy, transmitting apparatuscomprising an aerial, receiving apparatus removed a short distance fromthe transmitting apparatus and comprising a receiving aerial, abalancing aerial po nted at an angle to the receiving aerial and arecelvmg circuit coupled to both receiving and balancing aerials, andmeans for opposing the effect produced by the transmitting apparatus 'inthe receiving .aerial by the effect produced by the transmittingapparatus in the balancing aerial.

15. In a station forwireless telegraphy, the combination of transmittingapparatus comprising an aerial, receiving apparatus comprising areceiving aerial, and a balancing aerial tuned to the same periodicity,the receivingand balancing. aerials being pointed at an angle to oneanother, a receiving transformer inductively related to the twoprimaries at least one of said aerials being directive.

17. In a station for wireless telegraphy, a receiving aerial containingthe primary of a transformer, a balancing aerial pointed at an angle tothe receiving aerial and containing the primary of a transformer and areceiving circuit containing the secondary of a transformer surroundingthe two primaries and inductively related thereto.

I 18. In a station for wireless telegraphy, the combinatiouoftransmitting apparatus, receiving apparatus comprising two aerials,oneof which is directional, and means for opposing theefiect produced bythe transmitting apparatus in one aerial by the effect produced by thetransmitting apparatus in the other aerial.

19. In a station for wireless telegraphy, the combination of atransmitting aerial, receiving apparatus comprising two aerials one areceiving aerial and the other a bailancing aerial, the receiving aerialbeing located substantially parallelwith the transmitting aerial, andthe balancing aerial being located at an angle to the transmittingaerial.

20. In a station for wireless telegraphy, the combination of atransmitting aerial, receiving apparatus comprising two aerials, one areceiving aerial and the other a balancing aerial, the're ceiving aerialbeing located substantially parallel with the transmitting aerial,andthe balancing aerial bein" located at an angle to the transmittingaerial and pointing away from the transmitting aerial.

21. In a station for wireless telegraphy, transmitting apparatuscomprising an aerial,

receiving apparatus removed a short distance'from the transmittingapparatus and comprising a receiving aerial pointed parallelt'o thetransmitting aerial, a balancing aerialf pointed ting aerial, areceiving circuit coupled to both receiving and balancir g aerials,means for opposing the effect produced by the transmitting apparatus inthe receiving aerial bythe eii'ect produced by thetrans- 'mittingapparatus in the balancing aerial,

g circuit coupled balancing aerials,

v eliect produced by i in t1 2 receiving the trans at an angle to thetransmit- I 24:. In a system of duplex wireless telegraphy, a pluralityof stations each contain ing a transmitting aerial, a receiving aerialand a balancing-aerial at least one of said acrials being directive, thereceiving and balancing aerials of the several stations beingrespectively parallel.

25. In a system ot' duplex Wireless telegraphy, a plurality of stationseach.containing a transmitting aerial, and a balancing aerial, thetransmitting aerials of each sta tion being at an angle to the balancingaerials' of the others. I I

26. In a system of duplex wireless telegraphy, a plurality of stationseach containing a transmitting aerial and a balancing aerial, thebalancing aerial ofeach station pointing away from the transmittingaerial in that station and being at an angle to the transmitting aerialsof the other stations.

27. In a system of-duplex wireless telegraphy, a plurality of stationseachcontaining a transmitting aerial and a receiving aerial, thereceiving aerial of each station being in a plane parallel to the planeof the transmitting aerial in that station, and in the same plane as theplane ofthe transmitting aerials of the other stations. I I

28. In a system of duplex wireless telegraphy, a plurality of stationseaclrcontaining a transmitting aerial, a receiving aerial and abalancing aerial, the balancing aerial of each station being at an angleto the planes of the transmitting and receiving aerials of that stationand the transmitting aerials of the other stations.

29. In a system of duplex wireless telegraphy, a plurality of stationseach having a transmitting aerial, a receiving aerial, and a balancingaerial, the transmitting aerial of one station and the balancing andreceiving aerials of the distant stations with which it is desired tocommunicate being tuned to the same periodicity. I

30,, In a' system-oi. duplex wireless elegraphy, a plurality ofstationseach com: ising horizontal transmitting, receiving and m u ll=-balancin aerials. O

In a system of duplex wireless telegraphy, plurality of stations each coing transmitting aerial and horizon a. re cei balancing aerials.

a system of duplex wireless telegraphy, plurality of stations eachcomprisb l. receiving aerial and horizontal transritting and balancingaerials.

33. In a system of duplex wireless telegraphy, a plurality of stationseach comprisa r Hitting aerial, a receiving aerial balancii aerial,

eleg- Ql k ll compr 35. In a system of duplex wireless tele raphy, astation comprising a transmitting aerial, a receiving aerial and abalancing aerial, the balancing aerial being horizontally disposed andpointing away from the transmitting aerial, and the receiving aerialbeing horizontally disposed and parallel'to the transmitting aerial.

36. In a system of duplex wireless telegraphy, two stations eachcontaining a transmitting aerial, a receiving aerial and a balancingaerial, the balancing and receiving aerials of one station beinghorizontally disposed and respectively at an angle to and in the sameplane as the transmitting aerial of the other station.

37 In a system of duplex wireless telegraphy, two stations eachcomprising a transmitting aerial, a receiving aerial and a balancingaerial, the receiving aerial of each station being horizontally disposedand in' the same plane as and pointing awayfrom the transmittingaerialof the-other station, the balancing aerial of each station beinghorizontally disposed at an angle. to the transmitting aerial of theother station and pointing away from the transmitting aerial of its ownstation.

38. In a station for wireless telegraphy, the combination of atransmitting aerial, receiving apparatus comprising two aerials, one areceiving aerial and the other a balancing aerial, the balancing andreceiving aerials being located at substantially right angles to oneanother.

' 39; In a station for wireless telegraphy, the combination of atransmitting aerial, re-

ceiving apparatus comprisingv two aerials one a receiving aerial and theother a balancing aerial, the receiving aerial being locatedsubstantially parallel with the trans mitting aerial and the balancingaerial being located at substantially right angles to the transmittingaerial.

40. A' system of duplex wireless telegraphy, comprising a plurality ofstations each containing a transmitting aerial a balancing aerial and areceiving aerial, the balancing and receiving aerials at each stationbeing located at an angle to one another, but the receiving aerial atone station being located substantially parallel with the transnittingaerial at the other distant station.

41. A system of duplex wireless telegraphy, comprising a plurality ofstations each containing a transmitting aerial a balancing aerial andareceiving aerial, the balancing and receiving aerials at each stationbeing located at an angle to one another but the balancing aerial beinglocated at an angle to the transmitting aerial at the other distantstation,

42. A system of duplex wireless telegraphy, comprising a plurality ofstations, each station containing a transmitting aerial, a balamingaerial and a receiving aerial, the transmitting aerials at each stationbeing located in substantially the same plane, the receiving aerials atthe two stations being lo; cated in substantially the same plane and thebalancing aerials at each station being located at an angle to thetransmitting and receiving aerials at that station;

43., A system of duplex wireless telegraphy, comprising a plurality ofstations, each station contaming a transmitting aerial, a balancingaerial and a receiving aerial, the

transmitting aerials at the two stations being locatedlin substantiallythe same. plane with one another, but pointing away from one another,the receiving aerials being located in substantially the same plane butpointing away from one another, and'each balancing aerial being locatedat an angle to the transmitting aerial at its own station.

In witness whereof I have hereunto signed my name in the presence of twowitnesses.

\ GUGLIELMO MARCONI.

Witnessesz. i

W. L. MCEWEN,

WALTER S. JONES.

